Electric conductor adapted for use in process instrumentation

Abstract

An electrically insulated conductor adapted to be used at high temperatures in power plants, refineries and chemical process plants for connecting instruments has at least one pair of electrical conductors insulated with an irradiation cured ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer or polyvinyl chloride polymer and a drain wire enclosed in a metallic shield and an irradiation cured halosulfonated polyethylene, polychloroprene or chlorinated polyethylene jacket.

What is claimed is: 
     
       1. An electrical cable having improved dimensional stability and other properties which adapt it for use at elevated temperatures comprising at least two electrical conductors each having (1) an electrical insulating coating, said coating being an irradiation cured member selected from the group consisting of ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer and polyvinyl chloride, and (2) a protective jacket selected from the group consisting of irradiation cured halosulfonated polyethylene polymer, a polychloroprene and chlorinated polyethylene about the insulated conductors. 
     
     
       2. The product of claim 1 having a drain wire and an electrically conductive shield separating the insulated conductors and drain wire from the protective jacket. 
     
     
       3. The product of claim 2 wherein the said electrical insulating coating is an ethylene-tetrafluoroethylene copolymer and the jacket is chlorosulfonated polyethylene. 
     
     
       4. The product of claim 2 wherein the said electrical insulating coating is an ethylene-chlorotrifluoroethylene copolymer. 
     
     
       5. The product of claim 2 having a rip-cord disposed between the shield and the jacket. 
     
     
       6. A method of making an electrical cable having improved dimensional stability comprising providing at least two electrical conductors each having an electrical insulating coating, said coating being a member selected from the group consisting of an ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer and polyvinyl chloride, extruding a jacket selected from the group consisting of a chlorosulfonated polyethylene polymer, polychloroprene and chlorinated polyethylene over the insulated conductors, and subjecting the resulting product to irradiation until the polymer of the said jacket is cross-linked. 
     
     
       7. The method of claim 6 wherein the insulated conductors and a drain wire are twisted together, an electrically conductive shield is placed about the insulated conductors and a jacket is extruded over the shield. 
     
     
       8. The method of claim 6 wherein an electrically conductive shield is placed about the insulated conductors, a drain wire is placed in electrical contact with the shield and a jacket is extruded over the resulting assembly. 
     
     
       9. The method of claim 7 wherein the shield is a foil having a coating of a poly(alkylene)terephthalate ester and the drain wire is in electrical contact with the foil. 
     
     
       10. The product of claim 2 wherein the metallic shield has a poly(alkylene)terephthalate coating adjacent the jacket. 
     
     
       11. The method of claim 6 wherein the insulation on the conductors is ethylene-tetrafluoroethylene polymer and the jacket is chlorosulfonated polyethylene polymer. 
     
     
       12. The method of claim 6 wherein the uncured jacket is exposed to a dosage of from about 2 to about 20 Mrads. 
     
     
       13. An electrical cable adapted to be used at elevated temperatures comprising electrical conductors each electrically insulated with an insulating coating comprising an irradiation cured resin selected from the group consisting of ethylene-tetrafluoroethylene co-polymer, ethylene-chlorotrifluoroethylene co-polymer and polyvinyl chloride enclosed in a layer of irradiation cured synthetic resin selected from the group consisting of halosulfonated polyethylene polymer, a polychloroprene and a chlorinated polyethylene, said electrical conductors being twisted together to form a cable.